Publications

A total of 18,820 adult male pintails (Anas acuta) were trapped, banded, and released on Pel and Kutawagan marshes in south-central Saskatchewan in July 1955-58. Two hundred and fortyeight of these banded birds were recaptured on the same marshes during subsequent trapping operations, and 1,440 were recovered (shot or found dead) during legal hunting seasons, 1955-70. The size of the adult drake

No abstract available.

A disjunct breeding population of Gadwall in eastern North America was first recorded in 1939 This population has extended its range during recent years to the point where it is now found breeding in more than thirty locations (primarily National Wildlife Refuges and Wildlife Management Areas). These are 1,600-2,000 km (1,000-1,200 miles) from the main breeding range in the west and midwest. The n

An analysis of insoluble protein content of eye lenses from 59 known-age mallards (Anas platyrhynchos) indicated a slight increase between 8-9 months and 7 years of age. Nearly a complete overlapping of the insoluble protein content of individuals of different ages was apparent showing that the technique cannot be used to separate adult year classes of mallards. These results are contrary to fin

A method for monitoring changes in winter bird populations was tested in central Maryland in the winters of 1970, 1971 and 1972. A systematic sample of 41 transects was established to sample an area of 6150 sq. km. Each transect, located at the center of a standard 7 1/2-minute topographic map, was 8 km in length and approximately square in shape. Coverage began at local sunrise on any one day fro

An aerial survey in association with several intensive ground surveys yielded the first estimate of the size of the osprey (Pandion haliaetus carolinensis) nesting population in Chesapeake Bay. The 1973 population was estimated at 1,450 ± 30 pairs, of which 713 were on the western shore and 737 on the eastern shore. A small percentage of nonbreeders (possibly 2-5 percent) may be included in this e

A two-year Breeding Bird Atlas program for Montgomery County was undertaken by the Maryland Ornithological Society in 1971-1972. The county was divided into 65 5 km blocks and each block was assigned to an observer. Preliminary results show 46 to 93 species (mean 66) recorded per 5 km block and from 10 to 52 species (mean 28) confirmed per block. When the data are combined into 10 km block, the

Percutaneous absorption in vivo through the skin of the feet of the red-winged blackbird (Agelaius phoeniceus) has been investigated. Absorption after 18-24 hours exposure to 0.01 M solutions of salicylic acid, caffeine, urea, 2,4-D, dieldrin, diethylstilbesterol, and DDT was measured. Of these, only DDT and diethylstilbesterol were not absorbed to a measurable degree. The solvents ethanol, dim

No abstract available.

No abstract available.

Poisoning of North American waterfowl resulting from the ingestion of lead shot by ducks, geese, and swans causes an estimated annual mortality of 2 to 3% of the population (Bellrose 1959). To alleviate this problem the search for a suitable substitute for lead has been underway since the early 1950's. Proposed substitutes for lead shot were evaluated in a series of acute toxicity tests with pe

Tissues of adult, lead-dosed mallards that either died or were sacrificed were analyzed for lead. Lead levels in brains, tibiae, and breast muscle of ducks that died and in tibiae of ducks that were sacrificed increased significantly from dosage until death. Lead in the heart, lung, and blood from sacrificed ducks decreased significantly from dosage until death. Lead concentrations in tissues f